1. Technical Field
The invention relates to a junction or connection box, a use, a photovoltaic or solar panel, a contact element, and a method.
2. Related Art
Conventional solar or photovoltaic modules for generating electric energy from sunlight comprise one or more single solar or photovoltaic cells. Depending on the desired voltage and/or current to be provided by the solar module, the individual solar cells are connected in parallel and/or in series within the module and thus gathered in photovoltaic or solar cell groups. The solar cell groups are integrated in a flat solar module. The electrical terminals of the solar cell groups of the solar module are routed to the outside. In case of a partial decrease of the radiation intensity by sunlight onto individual solar cells or solar cell groups, for example by soiling or shading, the following effects may occur among others: (1) A (constant) decrease of the radiation intensity within the solar cell groups connected together leads to a reduced performance of the respective solar cell group. (2) If a solar cell within a solar cell group is partially shaded, this shaded solar cell acts as a blocking diode or resistor within the circuit of the solar cell group, which on the one hand may result in the entire solar cell group no longer being able to supply electric energy, and on the other hand in a damage of the shaded solar cell and thus to a permanent breakdown of the solar cell group.
In any case, different voltages may be applied between the routed-out terminals of the solar cell group of a solar module, depending on the radiation intensity onto the individual solar cells. A connection in series of the solar cell groups by corresponding circuiting of the terminals routed to the outside analogously leads to the above-mentioned problems.
In order to avoid the problems related with the differing radiation intensity of the solar cells, conventional so-called bypass diodes are used, which are electrically connected in an anti-parallel manner with respect to the solar cell groups. These bypass diodes have the effect that the current flow through the solar module is lead past solar cell groups that only supply low power, i.e. the terminals of this solar cell group of a solar module are short-circuited by the bypass diode and the corresponding cell group is bypassed thereby. Thus, such a solar cell group does no longer contribute to the overall performance of the solar module, but the overall current flow through the solar panel is substantially unobstructed and a damage of individual solar cell is avoided.
Therefore, in addition to the solar module, solar panels usually comprise an electrical junction or connection box with at least two contact devices and at least one bypass diode. The solar cells in a solar module are usually connected to each other by flat, thin conductor bands. These conductor bands are routed out of the solar module and manually contacted with an electrical terminal receptacle. The junction box of the solar panel therefore usually has an opening on the side facing the solar module, through which opening the conductor bands are routed through and connected to the contact elements. Conventionally, the junction box is subsequently filled with an insulating resin in order to fixedly connect the conductor bands with each other and to insulate them from each other. The solar module provided with the junction box is referred to as photovoltaic or solar panel.
Depending on the assembly method of a junction box to a solar module, wherein junction boxes may be mounted to a solar module for example manually or in an automated manner, the junction boxes are formed differently for different solar modules. It is therefore an object of the invention to provide a universal junction box that can particularly be employed within the framework of different assembly methods and thus allows a simple and cost-efficient assembly.
The objects are solved by the independent claims. Preferred embodiments are subject of the dependent claims.